Polyanhydrides have emerged as an important class of biodegradable polymers. Polyanhydrides have found widespread application in the controlled delivery of drugs, proteins, and vaccines. The conventional method of synthesizing polyanhydrides is by melt polycondensation of acetylated dicarboxylic acid prepolymers. This method affords high-molecular-weight polymers with good yields. Melt condensation polymerizations, however typically take about 1 to 3 hours to conduct. Additionally, the preparation and isolation of the acetylated prepolymer can take up to four days, including drying time and recrystallization.
Purity is an important consideration of polyanhydrides because these biocompatible polymers are often used for in-vitro and in-vivo studies. In this age of rapid drug discovery and advances in protein and macromolecular therapies, determining the correct polymer system and compositions are of the utmost importance to effectively stabilize the target drug. Therefore, there is considerable interest in the efficient synthesis of high-purity materials in a high throughput manner for material library screening. The rapid synthesis of some polymers through the use of microwave radiation and dielectric heating has been described in the literature (see for example, K. R. Carter, Macromolecules, 2002, 35, 6757). However, improved methods are needed to prepare high purity samples of polyanhydrides from diacids. New methods to prepare high purity polyanhydrides are also needed.